Hydrocarbon sludge treatment in upstream oil and gas ... sludge treatment in upstream oil and gas...
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Hydrocarbon sludge treatment in upstream oil and gas industry of Kuwait– Case Study Krishna Vangala Soil Remediation Group Kuwait Oil Company 24 th International Petroleum & Environmental Conference San Antonio, TX 30 Oct’17 – 1 Nov’17 Co-Authors : Mansour Al-Khareji, Soil Remediation Group Kuwait Oil Company
Transcript of Hydrocarbon sludge treatment in upstream oil and gas ... sludge treatment in upstream oil and gas...
Hydrocarbon sludge treatment in upstream oil and gas industry of Kuwait– Case Study
Krishna VangalaSoil Remediation GroupKuwait Oil Company
24th International Petroleum & Environmental ConferenceSan Antonio, TX30 Oct’17 – 1 Nov’17
Co-Authors : Mansour Al-Khareji, Soil Remediation GroupKuwait Oil Company
Regional Settings for the Sludge Treatment
• Harsh climate (0-58 0C)• High Wind speeds Sand erosion Sand storms
• Prior projects Limited pilots/demo studies No in-country vendors/labs
• Unfavorable site conditions Heavier fractions/Ashphaltin Ordnance clearance Site characterization
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THE ISSUE Historical legacy of KOC Oil & Gas
Exploration & Production operations havegiven rise to environmental pollution anddamage to the natural desertenvironment.
Typical non-operational redundantpolluted features include the following:
Effluent Pits (produced water) Sludge Pits (recovered oil from spills/leaks) Contaminated Soil Piles (oil soaked soil) Gatch Quarry Pits (construction purposes)
In addition, UXO remnants of war arepotentially associated with pollutedareas.
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CONTAMINATED FEATURES
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Effluent PitEffluent Pit Effluent Pit
Gatch Pit Sludge Pit ContaminatedSoil Pile
REMEDIATION SPECIFICATION
Primary Ecotoxic RS
� Soil within top 1.5m below finished grade;�Total PHC ≤ 5,580 mg/kg;�PAHs & BTEX compound specific;�Heavy Metals
Alternative Ecotoxic RS
�Soil within top 1.5m below finished grade;�Total PHC ≤ 10,000 mg/kg;�Salinity (≤ 4.5 dS/m, SAR 12); and
Commercial / Industrial RS
�Soil below 1.5m of finished grade;�Total PHC ≤ 30,000 mg/kg; and�PAHs compound specific.
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Remediation of Oil Contaminated Soils
Total Volume: 746,937m3
Remaining: 166,144m3
22%Treated:
580,793m3
78%Soil Washing
Thermal Desorption Bio-Remediation
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Soil Remediation Completion
Sludge Pit A1 – Before
Sludge Pit A1 – After
Gatch Pit A1 - Before
Gatch Pit A1 - AfterEffluent Pit C1- After
Effluent Pit C1- Before
Soil Remediation Completion
Sludge Pit A1 – Before
Sludge Pit A1 – After
Gatch Pit B2– Before
Gatch Pit B2 – After
Effluent Pit C2-Before
Effluent Pit C2-After
PREVIOUS PRESENTATIONS
Presented previous papers in lastseven IPEC conferences which dealtwith undertaken remediation works inKOC.
The remediation works hadcommenced in year 2012 :
Remediation Program overview Soil Remediation Oil recovery Results Lesson Learnt Way forward
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Characteristics of Sludge Pit Features
Sludge Pits• Large Size with a size ranging from :• 80m * 100 m• 300 m X 300 m• Depths ranging from 1-3m• 33 sludge pits and presence of sludge in other pits as well
• Earthen bunded features• The Pits consists of free/floating oil on the surface, saline
effluent underneath and oily sludge at the base of the feature.• The pits arise from the need to dispose of waste/surplus oil
resulting from shutdown, workover and maintenance operations of well heads and pipelines etc..
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SEQUENCE OF BIO REMEDIATION ACTIVITIES IN PICTORIAL DEPICTION
Dry & Wet Sludge Dry Sludge Tarcrete Crust
Dry Sludge Sludge & Oil
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SEQUENCE OF BIO REMEDIATION ACTIVITIES IN PICTORIAL DEPICTION
Sludge & Oil Holding Pit Sludge Melting
Stockpiled Sludge Tarcrete
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SEQUENCE OF BIO REMEDIATION ACTIVITIES IN PICTORIAL DEPICTION
Wet Sludge-1 Wet Sludge-2
Wet Sludge Removal-1 Sludge Removal-2
Sludge Volumes
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BOQSludge Volume
m3
SiteCharacterisationSludge Volume
m3
Lot A 77,900 24,147
Lot B 7,870 6,518
Lot C 33,450 9,951
Totals 116,220 40,616
Note : Oil generated from sludge is part of sludge treatment. Oil handed back to the Company from sludge treatment must meet the oil standard of ≤ 20% BS & W.
Classification of the Contamination & Sludge Scope
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Scope of Work
To conduct treatment of sludge following crude oil recovery, including physical stabilization, if required, by appropriate remediation techniques to achieve appropriate Remediation Standards (RS)
In addition, it was expected to undertake all treatment optimization trials to ensure the proposed remedial methods are suitable.
Classification of Contamination : Free phase oil Effluent Water Sludge Contaminated Soil
Sludge: sediments > 20% vol and < 70% vol, oil and/or water between 30% vol and 80% vol.
Sludge Characteristics
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HEM C6-C35
Avg (mg/kg)
HEM>C16-C35
Avg (mg/kg)
HEM >C35-C90
Avg (mg/kg)Total HEM
Avg (mg/kg)Total HEM
Max(mg/kg)
Lot A 26,400 25,400 277,000 481,000 752,000
Lot B 31,800 27,000 255,000 252,000 352,000
Lot C 106,000 206,000 368,000 775,000 866,000
Particle Size Analysis Results of Sludge Samples
Gravel+Sand
> 0.063 mm
Silt
0.063 – 0.002 mm
Clay
< 0.002 mmLot A 76.00 % 24.00 % 0 %Lot B 79.87 % 18.63 % 1.50 %Lot C 76.53 % 23.47 % 0 %
Sludge Characteristics
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Sample ID BS&W (Vol%) Oil Content (Vol%) Density
(g/cm)API Viscosity
(cSt)
98296828-1 76.6 23.4 0.96287 14.36 1205
98586871-1 72.7 28.3 0.96071 14.69 1703
97736740-1 21.8 78.2 0.95884 14.97 811
97266947-1 62.4 37.6 0.96741 13.69 2598
95507034-1 85.2 14.8 0.96217 14.47 1778
96257151-1 55.4 44.6 0.96353 14.26 6720
Soil Remediation Trials ( 1 to 4)
Indirect TDU (Trial 1) Bioremediation (Trial 2)
Direct TDU (Trial 3) Bioremediation (Trial 4 )
Sludge Pit A1 – After
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Sludge Treatment Methods- Trail 1Description Unit Batch 1 Batch 2 Batch 3PHC levels before mixing mg/kg 145,000 to 190,000
Mix Ratio (Sludge/Soil) - 1.5:1 1:1.5 1.5:1
PHC levels post mixing mg/kg 115,000 78,200 84,100
Total Volume m3 523 728 2,115Sludge Volume m3 314 291 1,269Treatment Rate m3/hr 5.0 5.0 5.0Treated Material - Sludge & Soil Sludge & Soil Sludge & SoilTechnology Used - Indirect TDU Indirect TDU Indirect TDUFinal PHC Concentration mg/kg 1,640 1,400 1,790
Observations - ITDU generated oil and oily sludge as by-product; frequent shut downs due to blockages by contaminated materials
Results - Stopped treating sludge using ITDU since no technology inplace to treat by-product
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Sludge Treatment Methods- Trail 2Description Unit Batch 1 Batch 2 Batch 3PHC levels before mixing mg/kg 65,800 to 95,000
Mix Ratio (Sludge/Soil) - None None 1:1
PHC levels post mixing mg/kg 88,400 65,800 46,400
Total Volume m3 530 2,400 4,479Sludge Volume m3 530 2,400 2,400Treatment Rate m3/hr 188 treatment days 137 treatment days 65 treatment daysTreated Material - Sludge Sludge Sludge & SoilTechnology Used - Bio-remediation Bio-remediation Bio-remediationFinal PHC Concentration mg/kg 88,400 65,800 6,640
Observations - PHC levels too high to initiate microbial growth.
PHC below 5% only can be treated using Bio
Results - Abandoned trial on unblended sludge. Blended option proved successful.
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Sludge Treatment Methods- Trail 3Description Unit Batch 1 Batch 2 Batch 3PHC levels before mixing mg/kg 145,000 to 190,000
Mix Ratio (Sludge/Soil) - 1:1 2:1 1:2
PHC levels post mixing mg/kg 123,300 77,800 56,250
Total Volume m3 2,640 355 600Sludge Volume m3 1,320 236 200Treatment Rate m3/hr 4.4 0.9 1.1Treated Material - Sludge mixed with Treated Soil in Soil Washing UnitTechnology Used - Direct TDU2 Direct TDU3 Direct TDU3Final PHC Concentration mg/kg 1,060 360 370
Observations - Low Sludge Treatment Rate
Results - Continuing Batch-1 but abandoned Batch 2 & 3 in TDU 3
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Sludge Treatment Methods- Trail 4Description Unit Batch 1 Batch 2 Batch 3PHC levels before mixing mg/kg 145,000 to 190,000
Mix Ratio (Sludge/Soil) - 1:25 None None
PHC levels post mixing mg/kg 84,500 48,400 43,800
Total Volume m3 26 25 25Treatment Rate m3 83 treatment days 83 treatment days 83 treatment daysTreated Material m3/hr Sludge & Soil Filter Cake SoilTechnology Used - Bio-remediation Bio-remediation Bio-remediationFinal PHC Concentration mg/kg 35,000 12,400 48,300
Observations - No PHC reduction for 56 days
Moderate degradation No Reduction
Results -Although trial results for Sludge/Soil blend and Contaminated Soil were barely encouraging, decided to continue bio-remediation for all blend types
Sludge Treatment Summary
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Trial 2• Sludge and
Blended sludge• Bio• Unsuccessful
beyond 5% PH
Trial 1• Blended sludge in
ITDU• Blockages• Unsuccessful
Sludge Treatment Summary
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Sludge mixed with Treated Soil
Direct TDULow Treatment Rate
Trial 3 Sludge, Filter Cake
& Soil
BioremediationNo meaningful degradation
Trial 4
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Sludge Proposals
Technology• Limited commercial technologies
Byproducts•All of them generating Byproducts
Large scale experience•Not available and seen missing info
Extremely difficult material to Treat
No proven technology barring TDU (Very low capacity)
Complete solution for sludge (oil, byproducts) yet to be seen
Landfill option is considered
Conclusion
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Thank youQ & A
Hydrocarbon sludge treatment in upstream oil and gas industry of Kuwait– Case Study
